Described herein is a set of toners, in which the set includes at least two different toner groupings forming a combination that is capable of exhibiting a substantially same color under ambient light conditions and in which at least one but less than all of the toners of the toner set includes some amount of a fluorescence agent, wherein upon exposure to activating energy, the fluorescence agent fluoresces to cause a visible change in the color of the toner grouping having the at least one toner containing the fluorescence agent.
A number of advantages are associated with the various embodiments described herein. For example, the toners with the fluorescence agent may be used to include security features in a document, including features to verify the authenticity of the document and/or to include digitally stored, machine readable or encrypted information in the document. Another advantage is represented by the possibility of printing customized security content on various forms and documents, a process known as Variable Data Printing, which is enabled by digital printing of security features. This is advantageous because it makes counterfeiting very difficult because each printed document must be attempted to be copied individually. The security information may be hidden in the document until exposed to activating energy or radiation such as UV light that causes the fluorescence agent to illuminate or fluoresce. The security information can then be viewed to verify the authenticity, or can be machine read to decode digitally stored encrypted information. The security information cannot be copied with existing photocopiers. Other advantages include that the two toner combinations may be made to exhibit the substantially same color in ambient light conditions, such that the presence of hidden information cannot be detected until exposed to the activating energy to initiate fluorescence, whereby at least one of the two toner combinations changes color to render the hidden information viewable/readable. Other advantages are apparent from the description herein.